Field of the Invention
This disclosure relates to a detection apparatus configured to detect a mark, an imprint apparatus provided with the detection apparatus configured to detect the mark, and a method of manufacturing products by using the detection apparatus and the imprint apparatus.
Description of the Related Art
An imprint technology is known as a technology for manufacturing semiconductor devices. The imprint technology is a technology for forming a pattern on an imprint material supplied onto a substrate by using a mold having a pattern formed thereon.
PCT Japanese Translation Patent Publication No. 2008-522412 discloses an imprint apparatus provided with a detection apparatus configured to detect an alignment mark formed in a shot area on a substrate and an alignment mark formed on a mold simultaneously. The detection apparatus disclosed in PCT Japanese Translation Patent Publication No. 2008-522412 includes the alignment marks formed on the mold and the substrate respectively and including grid patterns having grid pitches in a direction for measuring a relative position, and achieves die-by-die alignment between the mold and the substrate on the basis of a result of detection of phases of a moire pattern formed of both of the grid patterns.
In the detection apparatus, the both grid pitches of the grid pattern on the substrate and the grid pattern on the mold in the direction of measurement are slightly different from each other, and if the both grid patterns are overlapped each other, diffracted light from both grid patterns interferes with each other and generates a moire pattern having a cycle reflecting the grid pitch difference. When the relative position of the grid patterns changes in the measuring direction, the phase of the moire pattern changes as well. Therefore, alignment between the substrate and the mold is achieved by detecting the phase of the moire pattern.
In order to detect the moire pattern and achieve the alignment between the substrate and the mold, it is necessary to evaluate performances of the detection apparatus itself first. By actually using the cycle of the moire pattern obtained from the grid pitch difference between the respective grid patterns on the substrate and the mold and an image of a cycle of a moire pattern picked up by an image-pickup unit of the detection apparatus, an optical magnification (a magnification of an optical system) as one of optical performances of the detection apparatus may be evaluated.
The detection apparatus provided in the imprint apparatus of the PCT Japanese Translation Patent Publication No. 2008-522412 cannot detect the moire pattern unless the grid pattern formed on the substrate and the grid pattern formed on the mold overlap each other. Therefore, the performances of the detection apparatus cannot be evaluated without using the substrate and the mold having the grid patterns formed thereon.